铁离子对麦草秸秆酶解的影响

Effect of Fe^(3+) on enzymatic hydrolysis of wheat straw

以预处理的麦草秸秆为底物,考察了铁离子促进酶解麦草秸秆的优化工艺条件以及对体系酶动力学、酶活和酶构象的影响,并用扫描电镜对底物进行分析。固定底物12.5g/L时,最佳酶解工艺条件为:时间50h,温度50℃,酶3.0g/L,Fe^(3+)0.3g/L,纤维素转化率为51.45%,比不含Fe^(3+)的对照组提高了27.21%。Fe^(3+)的加入提高了酶解反应的最大反应速率和酶活,最大反应速率提高了33.87%,相对酶活的提高率最高为36.14%。扫描电镜结果表明,预处理后麦草秸秆变得蓬松,含Fe^(3+)的体系酶解后的底物孔洞较多,铁离子对预处理后麦草有较好的酶解促进作用。

The enzymatic hydrolysis of pretreated wheat straw was carried out in the presence of Fe^3+ and the conditions were optimized.The effects of Fe^3+ on activity and conformation of enzyme,kinetics of enzymatic hydrolysis and the morphologies of substrates were investigated.The optimized conditions were 3.0 g/L mass concentration of the enzyme,0.3 g/L mass concentration of Fe 3+ at 50 ℃ for 50 h with substrate concentration of 12.5 g/L.Under the conditions,the conversion efficiency of cellulose was 51.45%,which was 27.21% higher than the controlled sample without Fe^3+.The addition of Fe^3+ increased the maximum hydrolyzed rate and the relative activity of enzyme.The maximum hydrolyzed rate increased by 33.87% and the relative activity of enzyme was enhanced by 36.14%.The result of scanning electron microscopy showed that the wheat straw became fluffy after pretreatment,and the substrate had porous structure after enzyme hydrolysis,especially in the system containing Fe^3+.Therefore,Fe^3+ was facilitated to the enzymatic hydrolysis of pretreated wheat straw.